Racine carré

[missdodo]

tjs du mal pour cet exo :

on va dire que le " V " correspond a la racine :

a/ V98-V450+V72
b/ (2V5-5V2)(V2+V5)
c/ (V3+V2)²+(V6-1)²-(V3+V8)²
d/ (V15-V3) / (V6-1)

mercii davance

[olivthill]

V98-V450+V72

98 = 2 x 49 = 2 x 7 x 7
donc v98 = 7v2

450 = 2 x 225 = 2 x 5 x 45 = 2 x 5 x 5 x 9 = 2 x 5 x 5 x 3 x 3
donc v450 = 15v2

72 = 2 x 36 = 2 x 2 x 18 = 2 x 2 x 2 x 9 = 2 x 2 x 2 x 3 x 3
donc v72 = 6v2

donc V98-V450+V72 = ...

[olivthill]

b/ (2V5-5V2)(V2+V5)

=2v5xv2 +2v5xv5 -5v2xv2 -5v2xv5
car (a-b)(c+d) = ac +ad -bc -bd

=2v5xv2 +2x5 -5x2 -5v2xv5

et v2 x v2 = 2
v5xv2 = v2xv5

=-3v5xv2